Any way to guage what my % HR is during cardio w/o monitor

[pg600rr]

I have been doing full out running once in the a.m. and once in the p.m. 5 days a week and doing about 1.5-2miles each time for a total of 3-4 miles a day... i have been reading on here that it is best to run at 65% MHR to preserve muscle and lose BF, so I calculated mine to be 128@ 65%..not sure if that sounds right but I am 23 yrs. Anywyas I do not have a heart rate monitor... any possible way to estimate how much effort it would take to be in this zone? a light jog, a speed walk, steady pace running, running fast, or sprinting? right now I usually sprint out for about 2 mins and then speed walk for a min. and keep that up for the 1.5-2miles....

[Motion]

I calculated my heart rate and bought a heart rate monitor to make sure I was in my "zone", turns out I was doing the exact right speed already. Still a nice thing to have though.

[pg600rr]

where did you get it and how much was it??

[Motion]

where did you get it and how much was it??

Amazon.com $40

[helium3]

i know when im in the zone as i breath deep but can just hold a conversation down(not with myself )